A passive optical network (Passive Optical Network, PON) does not include an electronic component or electrical power supply but includes an optical line terminal (Optical Line Terminal, OLT) that is installed at a central control station and a batch of matching optical network units (Optical Network Unit, ONU) that are installed at a user site. An optical distribution network (Optical Distribution Network, ODN) between the OLT and the ONUs includes optical fibers, a passive optical splitter or a coupler, and the like. The ODN is formed by passive components such as an optical splitter (Splitter), without requiring an expensive active electronic device.
An access network of a next generation develops towards high bandwidth of 10G. The PON network is subject to a 1:64 or even 1:128 application. In the prior art, an optical module on the OLT side has low output optical power. Therefore, the ONU side needs to use a high-sensitivity component. For example, a 10G optical module on the OLT side uses an electro-absorption modulated laser (Electro-absorption Modulated Laser, EML) to transmit an optical signal, and its specification of the output optical power is 2-6 dBm. To meet a power budget need of 29 dBm specified in a related protocol, sensitivity on the ONU side needs to reach 2-29=−27 dBm. At present, such a power budget can be implemented only by a high-sensitivity APD chip. Moreover, the APD chip works in a multiplication mode. When input optical power increases, the APD chip is more prone to burn. Therefore, in the prior art, the low output optical power of an optical module greatly restricts use of optical components on the ONU side, and severely hinders development of the access network towards high bandwidth.